Art of and apparatus for recording and reproducing sound.



'V. H. EMERSON & G A. MANWARING.

ART OF AND APPARATUS FOR RECORDING AND REPRODUOING SOUND.

APPLICATION FILED APR.17, 1908.

1,055,525, Patented Mar.11,1913.

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having a spiral blank space, or succession of spaces, (where no ink hasbeen deposited). This. blank space 30 corresponds to the superficialshape of the record-groove of the printing-plate (and of the originalsound-record). The paper may be any ordlnary paper; or it may be treatedbefore ent No. 30,278, dated June 17, 1890 (Fig.

9 thereof) and it differs from the tracing shown in Fig. 5 of BerlinerPatent No.- 732,786, dated Nov. 8, 1887, in that the line y of thelatter is not of varying width,

nor is it described as translucent.

Referring now to Fig. 2, 11 is a table or frame-plate, beneath which isindicated a battery 12 having the circuit 13-13. At 14 is the core, andat 15 the windings, of an electro-magnet in the circuit 13, in front ofwhich magnet is a suitably-supported diaphragm 16, from which extends asoundduct 17, leading to the horn 17. The'sele nium cell included in thecircuit. 13, is indicated at 18. Broadly stated, we provide in theelectric circuit'a selenium cell and a telephone. In front of theselenium cell, we rovide a revoluble and laterally-progress- 1ng carrier19, which may be a sort of spider or ring (or a disk of glass or othertransparent material) u on which our stencil record 20 is detacha lysecured by any convenient device (not shown). On the front side of therecord 20, we locate a lamp or other source of-light 21; and, betweenthe record 20 and the selenium cell is an opaque shield 22 having anarrow transverse slit 23 (see Fig. 3.). The selenium cell will furtherbe protected from light by a removable o aque housing 24. Suitable means(not s own) are provided for rotating the carrier 19 and the record 20,while causing them to progress laterally in front of slit 23.

The operation is now obvious: When the apparatus is started, the stencilrecord 20 is caused to revolve and to progress in front of the slit'23,the rate of progression being correlatedto the pitch of the spiralrecordpath 30; so that this blank space 30 will, in

' its successive convolutions, be passing continuously in front of theslit. The stencil record 20 acts as sort of shutter in admitting more orless light through the slit 23 and upon the selenium cell 18; the widerthe blank space 30, the more light will be admitted to the seleniumcell; and the longer each particular lake or enlargement in the blankspace, the longer will be the period of time in which light is beingadmitted to the selenium cell. In short, the quantity of light admittedto the cell, and the duration of the admission of light, correspondexactly to the intensity and duration of the original sound-waves. Fromthis it follows fromthe principle of the selenium cell, that itselectrical conductivity is increased and diminished precisely inaccordance with the sound-waves; consequently the electro-mag net let-15has its energy increased and diminished in precise accordance with thesound-waves; and the diaphragm 16 is vibrated accordingly, and givesforth sounds corresponding precisely to the original sounds whose waveshad'been recorded and then copied graphically upon the stencil record20.

It will be understood of course that the apparatus just described ismerely one embodiment of an apparatus for carrying out our invention,and for utilizing a stencil record obtained as heretofore described orotherwise.

While we have described our record as in the form of a disk having thetranslucent spaces arranged in a spiral, it is manifest that a tape, oran endless belt, might be employed; and the translucent spaces mightextend in a continuous straight line or otherwise. Furthermore, theterms opaque and translucent are relative, the gist-of this part of ourinvention consisting in the sound-record having variations oftranslucency corresponding to sound-waves. For instance, the pathindicating the soundwaves might be the opaque portion .while the fieldof the record would be translucent; and the wholev article might be moreor less translucent, but the part corresponding to path 30 markedly moreso and with its translucency varying in accordance with sound-waves.Such articles would still be within the spirit ofour invention. Again,since the two sides of the record-path 30 are similar, only one side ofsuch record might be employed for obtaining audible reproductions.Therefore, the employment, in modulating the admission of light to theselenium cell, of a zig-zag record-path of uniform width, as illustratedin Fig. 5 of mentioned), by using only one-half of such record, would bewithin the spirit of our invention. It will also be understood that ourstencil record may be obtained by other means or processes than aboveset forth. And other changes may be made in the construction andarrangement, and in details, without in any case departing from thespirit of our invention, which broadly consists,.first; of asound-record presenting variations of translucency corresponding tosound-waves; and, second, in reproducing sounds by mod;

the Berliner Patent No. 7 32,786 (heretofore of varying Widthcorresponding to sound- Waves, and then producing therefrom upon a sheetof suitable material a sound-record ulating (in accordance withsound-Waves) the amount of light admitted upon a selenium cell, andthereby correspondingly actuating the diaphragm of the talking-machine.

Having thus described our invention, We claim:

1. The process of record, Which consists ferent from that of the rest ofthe sheet, the Widths of said areas varying in accordance With thesound-Waves.

The process of producing a soundof first producing in producing a soundatablet of suitable material a record-groove record, Which consists offirst producing in of varying Width corresponding to sounda tablet ofsuitable material arecord-groove Waves, obtaining therefrom in hardmateof varying Width corresponding to soundrial an exact duplicate ofsaid original record-groove, and finally printing the surface of thelatter upon a translucent sheet. I

' 2. The process of producing a soundrecord, which consists of producingin suitable material a record-groove of varying Width corresponding tosound-Waves, and printing 7 therefrom upon a translucent Waves, and thenproducing therefrom an opaque sheet having a translucent path of waves.

In testimony whereof We have signed this specification in the presenceof two subscribing Witnesses.

vIoToR 'H. EMERSON.

sheet. v GEORGE A. MANWARING..

3. The process of producing a sound-. Witnesses:

record, Which consists of first producing in RALPH L. SCOTT,

a tablet of suitable material a record-groove W. H. HARTING.

consisting of areas having translucency difvarying Width correspondingto sound-

